Marans tend to lay a nice sized brown egg. They are well known for laying a dark chocolate brown egg, but in practice the colour can vary from lighter brown to darker brown and sometimes also speckley.  Even within the same hen changes in egg colour can occur – usually being a gradual change from darker brown at the beginning of her egg laying cycle to a paler brown by the end (often returning to a darker brown again at the beginning of the next).

Below is a photo from Keeping Chickens Newsletter subscriber Brad of eggs from his Black Copper Marans.